<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // 编写一个函数，计算三个数字的大小，按从小到大顺序输出


        function  size(a,b,c){
            var num,a,b,c;
           if(a>b){
            num=a;
            a=b;
            b=num
           }
           if(b>c){
            num=b;
            b=c;
            c=num
           }
           if(a>b){
            num=a;
            a=b;
            b=num
           }
           document.write(a+" "+b+" "+c)
        }
        size(3,9,4)
    </script>
</body>
</html>